Higher armor values can be thought of as increasing your effective health in relation to incoming damage. However, this would only apply to damage types that do not ignore armor. Because "effective health" more literally translates as "the maximum amount of damage you can take", if we simply set your "Total Health" equal to your "Incoming Damage" after Damage Mitigation, and then solve for the Incoming damage alone, we can determine your Effective HP.

As Armor Increases, Damage Mitigation values decrease, and therefore Effective HP drastically increases. Below are two tables with examples of how Effective HP increases with armor. All values are rounded to the nearest integer.